diff -r 000000000000 -r 6474c204b198 browser/components/tabview/test/browser_tabview_bug596781.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/tabview/test/browser_tabview_bug596781.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,41 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+let newTab;
+
+function test() {
+  waitForExplicitFinish();
+
+  newTab = gBrowser.addTab();
+  gBrowser.pinTab(newTab);
+
+  window.addEventListener("tabviewshown", onTabViewWindowLoaded, false);
+  TabView.toggle();
+}
+
+function onTabViewWindowLoaded() {
+  window.removeEventListener("tabviewshown", onTabViewWindowLoaded, false);
+  ok(TabView.isVisible(), "Tab View is visible");
+
+  let contentWindow = document.getElementById("tab-view").contentWindow;
+
+  is(contentWindow.GroupItems.groupItems.length, 1, "Only one group exists"); 
+  is(gBrowser.tabs.length, 2, "Only one tab exists");
+  ok(newTab.pinned, "The original tab is pinned");
+
+  let groupItem = contentWindow.GroupItems.groupItems[0];
+  is(groupItem.$closeButton[0].style.display, "none", 
+     "The close button is hidden");
+
+  gBrowser.unpinTab(newTab);
+  is(groupItem.$closeButton[0].style.display, "", 
+     "The close button is visible");
+
+  let onTabViewHidden = function() {
+    window.removeEventListener("tabviewhidden", onTabViewHidden, false);
+    gBrowser.removeTab(newTab);
+    finish();
+  }
+  window.addEventListener("tabviewhidden", onTabViewHidden, false);
+  TabView.toggle();
+}